Vol. xxix] ENTOMOLOGICAL NK\VS. 133 



the bark of a dead black ash (Fra.riuus niqra Marsh.) at Hum- 

 melstown, Pennsylvania, July 21, 1917. Type: A male in the 

 author's collection. 



The larvae had worked through the bark and transformed 

 to the adult stage without entering the sapwood. 



I believe that Mr. F. C. Craighead took the same species 

 from an ash tree at Great Falls, Virginia, in 1916. 



New North American Diptera (Scathophagidae). 



By E. T. CRESSON, JR., Academy of Natural Sciences of 



Philadelphia. 



Grthacheta amoena new species. 



<? . Black; frontalia, antennae, halteres, lateral margins of abdomen, 

 legs except hind tarsi, tawny. Face, cheeks, palpi, squamae, and fore 

 coxae, white. Wings brownish with decided intensification along costa. 

 Opaque ; frontal orbits, occiput, ocellar tubercle, thorax except mes- 

 onotum, abdomen except dorsum, cinereous. Mesonotum brownish with 

 fine dorso-central black stripes ; scutellum and abdomen also brownish 

 All bristles black. 



Slender; head as broad as thorax. Frons nearly .3 width of head; 

 orbits parallel; three proclinate frontals. Antennae .8 length of face; 

 third joint 3 times as long as second with acutely prominent apical 

 angle ; arista micro-plumose. Palpi nearly as long as horny proboscis. 

 Oral margin, each side, with 2-3 bristles besides the vibrissa. Thoracic 

 chaetotaxy : D. C. 2:3, Hum. 1-2, Presut. i, Np. 2, Sa. 2, Pa. 2, Ppl. 2, 

 Stigma I, Mpl. 2-3, Spl. 3. Scutellum triangular, narrowly trrncate 

 with 4 long bristles ; the apical pair cruciate and at extreme apex. Ab- 

 domen 1.5 times as long as broad, narrower than thorax; segments 

 2-4 each with a long, erect bristle on apical lateral margins ; 5-6 each 

 with 4 erect apical marginal bristles; lobes of fifth ventral, suspended, 

 twice as long as broad, with roundly pointed apices, sparsely pilose. 

 Legs long and slender, especially the femora. Chaetotaxy : Fore 

 femora with post. fl. and ext. series long and slender; fore tibiae with 

 2 ant. ext., i post. ext. and fl.; middle femora with i ant. fl., 3-4 ant., 

 2 subap. post., 2-3 fine, long post. fl. ; middle tibiae with i ant. fl., 2 

 ant. ext., 2 long post, ext., i post, fl.; hind femora with 3 fine long 

 fl., 1-2 ant. fl., 6 ant. ext. ; hind tibiae with I ant. fl., 3 ant. ext., 3 post. 

 ext. Wings long and narrow; costa without spine at first; veins 3-4 

 curved and parallel; penult, and tilt, of fourth subequal ; ult. of fifth 

 .5 as long as post. c. v. ; anal vein attaining margin. Length. 6 mm. 



